The goal of the proposed program is to address several technical feasibility questions (in Phase I), and then demonstrate (in a subsequent Phase II) a compact affordable device for operator-independent monitoring of blood volume flow, particularly in the setting of hemodialysis treatment for those with end-stage renal disease (ESRD). Phase I specific aims will investigate the feasibility of using Sonetics'CMUT-in-CMOS ultrasound transducer technology to build an ultrasound array with a steerable transmit beam and a digitally-controlled receive aperture. System-level hardware and software will be developed to control the array operation and to capture Doppler signals indicative of volume flow. Phase I experiments with this array will evaluate its ability to reduce operator-dependence and to achieve good flow-sensing ability while maintaining a compact, low profile that will not interfere with dialysis treatment. Feasibility will also be determined for using this array to obtain vessel-size and insonification angle information, such that the array could be employed to meet the broader need for accurate blood volume flow measurements outside of the ESRD setting. In Phase II, the array, together with electronics for automated control, signal acquisition, and possibly wireless communication will be integrated into an ultra-compact flow-sensing patch. The clinical market stands to benefit greatly from this innovation, given that over 330,000 patients suffer from ESRD in the US alone. These patients require dialysis treatment three times per week, which costs the U.S. healthcare system over $10 billion annually. Maintaining healthy vascular access for dialysis treatment is a difficult and important problem, which accounts for over 10% the cost of dialysis care. Regular access monitoring has been shown to significantly reduce access failures, and with the frequent low-cost monitoring that would be possible with the device proposed here, failure rate would be even lower. This would have wide- ranging benefits, enabling better patient outcomes, reducing staffing needs, and reducing the skyrocketing costs in the U.S. healthcare industry. PUBLIC HEALTH RELEVANCE: Potential benefits to public health from the successful development of Sonetics'novel ultrasound-based flow monitor include: reduced health complications for dialysis patients receiving treatment for end-stage renal disease, reduced staffing needs as flow- monitoring devices become less operator dependent, and reduced health-care costs for society as a whole, as dialysis patients place a lower demand on the health-care system. Furthermore, if automated blood flow sensing becomes more widely deployed, health outcomes will improve for additional patient populations such as those with peripheral arterial disease.